codify "platform" into resolution logic, server-fn/fullstack overhaul (#4596)

overhaul dioxus fullstack using a new implementation of server_fn

This PR is a complete rewrite of dioxus fullstack designed to improve compatibility with axum and to fix a number of compilation errors based on feature flag unification plumbing through macros.

packages/playwright-tests/fullstack.spec.js

@@ -95,7 +95,7 @@ test("assets cache correctly", async ({ page }) => {
 
   // Wait for the asset image to be loaded
   const assetImageResponse = await assetImageFuture;
-  console.log("Asset Image Response:", assetImageResponse);
+  // console.log("Asset Image Response:", assetImageResponse);
   // Make sure the asset image cache control header does not contain immutable
   const assetCacheControl = assetImageResponse.headers()["cache-control"];
   console.log("Cache-Control header:", assetCacheControl);